Pallets, e.g., wood pallets, are used to store and transport loads of a vast range of goods. For example, a pallet can be used to transport boxes of goods that have been stacked and stretch wrapped or otherwise secured upon the pallet from a manufacturer to a point of sale. Of course, a pallet carrying a full load can be very large and heavy and, therefore, difficult, dangerous and time consuming to move within a warehouse, for example. And oft times two loaded pallets are stacked one on top of the other for handling time and/or storage efficiency reasons.
One type of known pallet moving and stacking system simply employs a first forklift truck to move a first loaded pallet to a stacking location, whereat either the first forklift truck must retrieve a second loaded pallet to stack upon the first loaded pallet, or a second forklift truck is employed to stack the second loaded pallet upon the first loaded pallet. Then, a forklift truck must lift the first and second stacked and loaded pallets from the stacking area and move them to a storage location. This system for moving and stacking pallets is time consuming and can be dangerous. Using a first forklift truck with or without a second forklift truck helping stack loaded pallets requires the time and attention of at least one employee, and is relatively slow. Because using forklifts requires at least one forklift operator, moving and stacking pallets by this system also is prone to human error. For example, an operator could have an accident, toppling an upper loaded pallet from a lower loaded pallet on the forklift, and possibly endangering other employees.
Automated pallet moving and stacking systems are also known in the prior art. In a first type of stacking system, a vertically adjustable fork travels generally horizontally back and forth perpendicular to a conveyor. The fork picks up a first loaded pallet provided on the conveyor, and elevates that pallet above the conveyor. A second loaded pallet is conveyed into position under the elevated first pallet which is then set down upon the second loaded pallet. This system has a large operating footprint. That is, the conveyor and traveling fork system takes up a significant space within a warehouse, along a loading dock, or other location having a large enough floor space which could otherwise be used more efficiently.
In a second known automated pallet stacking system, a conveyor transports a first loaded pallet to a scissors-lift table. The scissors-lift table lifts the first loaded pallet and, in the lifted position, a fork engages the pallet. The scissors-lift table then retracts back to the level of the conveyor. A second loaded pallet is then conveyed to the scissors-lift table. The scissors-lift table raises the second loaded pallet into engagement with the first loaded pallet held by the retractable fork. The fork then retracts from engagement with the first loaded pallet, the scissors-lift table is lowered, and the first and second loaded pallets are thereafter moved away from the scissors-lift table to a desired location. In order to use a scissors-lift table system, an existing conveyor system must be retrofitted to accommodate the scissors-lift table itself. And this system also uses significant floor space because of the retractable fork.
In the above mentioned automated systems which are hydraulic powered, maintenance is time consuming, difficult and messy when dealing with hydraulic fluids. Also, the hydraulic systems are expensive to maintain and require compliance with environmental regulations regarding hydraulic fluid disposal.
Therefore, there is a need for an improved stacking system for loaded pallets whereby the efficiency of stacking loaded pallets is enhanced over prior art systems.
There is also a need to provide an improved system for stacking loaded pallets which occupies less space, i.e., has a smaller floor footprint, than prior art pallet stacking systems.
There is yet also a need to provide an improved stacking system for loaded pallets in which cost and frequency of maintenance is reduced relative to prior art systems.